The present invention relates to a method for the treatment or prevention Flaviviridae viral infection using nucleoside analogues.
Hepatitis is a disease occurring throughout the world. It is generally of viral nature, although there are other causes known. Viral hepatitis is by far the most common form of hepatitis. Nearly 750,000 Americans are affected by hepatitis each year, and out of those, more than 150,000 are infected with the hepatitis C virus (HCV).
HCV is a positive-stranded RNA virus belonging to the Flaviviridae family and has closest relationship to the pestiviruses that include hog cholera virus and bovine viral diarrhea virus (BVDV). HCV is believed to replicate through the production of a complementary negative-strand RNA template. Due to the lack of efficient culture replication system for the virus, HCV particles were isolated from pooled human plasma and shown, by electron microscopy, to have a diameter of about 50-60 nm. The HCV genome is a single-stranded, positive-sense RNA of about 9,600 bp coding 30 for a polyprotein of 3009-3030 amino-acids, which is cleaved, post-translationally by cellular and two viral proteinases into mature viral proteins (core, E1, E2, p7, NS2, NS3, NS4A, NS4B, NS5A, NS5B). It is believed that the structural proteins, E1 and E2, the major glycoproteins are embedded into a viral lipid envelop and form stable heterodimers. The structural core protein interacts with the viral RNA genome to form the nucleocapsid. The genes or regions designated NS2 to NS5 code for nonstructural proteins some of which have enzymatic functions involved in virus replication and protein processing including a polymerase, protease and helicase.
The main sources of contamination with HCV is blood. The magnitude of the HCV infection as a health problem is illustrated by the prevalence among high-risk groups. For example, 60% to 90% of hemophiliacs and more than 80% of intravenous drug abusers in western countries are chronically infected with HCV. For intravenous drug abusers, the prevalence varies from about 28% to 70% depending on the population studied. The proportion of new HCV infections associated with post-transfusion has been markedly reduced lately due to advances in diagnostic tools used to screen blood donors.
The treatment currently available for HCV infection is interferon (IFN), ribavirin, and a combinaison of the two (REBETRON). However, according to different clinical studies, only 70% of treated patients normalize alanine aminotransferase (ALT) levels in the serum and after discontinuation of IFN, 35% to 45% of these responders relapse. In general, only 20% to 25% of patients have long-term responses to IFN. On the other hand, pilot studies suggest that combination treatment with IFN plus Ribavirin (RIBA) results in sustained response in the majority of patients. Different genotypes of HCV respond differently to IFN therapy, genotype 1b is more resistant to IFN therapy than type 2 and 3.
There is therefore a great need for the development of therapeutic agent for treating or preventing Flaviviridae viral infection.
The present invention provides a method for treating or preventing a Flaviviridea viral infection in a host comprising administering a therapeutically effective amount of at least one compound selected from: 
or a pharmaceutically acceptable salts thereof, wherein:
R is H, xe2x80x94NR2R3 or OR4 wherein
R2 is H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-8cycloalkyl;
R3 is H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl;
R4 is H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl; and
Z is H, OR4xe2x80x2, or xe2x80x94NR2xe2x80x2R3xe2x80x2 wherein:
R2xe2x80x2 is H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-8cycloalkyl,
R3xe2x80x2 is H, C1-6 alkyl, C2-6 alkenyl, or C2-6 alkynyl;
R4xe2x80x2 is H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl; and and;
Y is N or Cxe2x80x94X;
X is chosen from of H, halogen, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, CN, CF3, N3, NO2, C6-10 aryl, C6-10 heteroaryl and CORb wherein Rb is chosen from of H, OH, SH, C1-6 alkyl, C1-6 aminoalkyl, C1-6 alkoxy and C1-6 thioalkyl;
and Ra is chosen from of H, monophosphate, diphosphate, triphosphate, carbonyl substituted with a C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C6-10 aryl, and 
wherein each Rc are independently chosen from H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl and an hydroxy protecting group,
wherein said nucleoside is present in the form of the (xe2x88x92) enantiomer, the (+) enantiomer or mixtures thereof, including racemic mixtures.
The present invention provides a method for treating a Flaviviridea viral infection in a host comprising administering a therapeutically effective amount of at least one compound as described in the present application.
The present invention provides a method for preventing a Flaviviridea viral infection in a host comprising administering a therapeutically effective amount of at least one compound as described in the present application.
The present invention provides a method for reducing the biological activity of a Flaviviridea viral infection in a host comprising administering a therapeutically effective amount of at least one compound as described in the present application.
In another aspect, there is provided a pharmaceutical formulation comprising the compound of the invention in combination with a pharmaceutically acceptable carrier or excipient.
Still another aspect, there is provided a method for treating or preventing a Flaviviridea viral infection in a host comprising administering to the subject a combination comprising at least one compound according to formula I or formula II and at least one further therapeutic agent.
In another aspect of the invention is the use of a compound according to formula I, for the preparation of a medicament for treating or preventing a viral infections in a host.
In another aspect of the invention is the use of a compound according to formula II, for the preparation of a medicament for treating or preventing a viral infection in a host.
In one embodiment, the viral infection is chosen from Flaviviridea viral infections.
In one embodiment, the Flaviviridea viral infection is chosen from of Hepatitis C virus(HCV), bovine viral diarrhea virus(BVDV), hog cholera and yellow fever.
In an other embodiment, the Flaviviridea viral infection is Hepatitis C.
In one embodiment, there is also provided a method for inhibiting or reducing the activity of viral polymerase in a host, when compared to a standard comprising administering a therapeutically effective amount of a compound having the formula I.
In one embodiment, there is also provided a method for inhibiting or reducing the activity of viral polymerase in a host, when compared to a standard, comprising administering a therapeutically effective amount of a compound having the formula II.
In one embodiment, there is also provided a method for inhibiting the activity of viral polymerase in a host, when compared to a standard comprising administering a therapeutically effective amount of a compound having the formula I.
In one embodiment, there is also provided a method for inhibiting the activity of viral polymerase in a host, when compared to a standard, comprising administering a therapeutically effective amount of a compound having the formula II.
In one embodiment, there is also provided a method for reducing the activity of viral polymerase in a host, when compared to a standard comprising administering a therapeutically effective amount of a compound having the formula I.
In one embodiment, there is also provided a method for reducing the activity of viral polymerase in a host, when compared to a standard, comprising administering a therapeutically effective amount of a compound having the formula II.
In another embodiment, the viral polymerase is HCV polymerase.
In one embodiment, the compounds and methods of the present invention comprise those wherein the following embodiments are present, either independently or in combination.
In one embodiment, R4 is C1-6alkyl.
In one embodiment, R4 is methyl or ethyl.
In one embodiment, R is NH2, H or OH.
In a further embodiment R is NH2 or OH.
In a further embodiment R is OH.
In one embodiment R is xe2x80x94NR2R3 wherein R2 is C3-8cycloalkyl and R3 is H.
In one embodiment R is xe2x80x94NR2R3 wherein R2 is C3-5cycloalkyl and R3 is H.
In one embodiment R is xe2x80x94NR2R3 wherein R2 is cyclopropyl or cyclopentyl and R3 is H.
In one embodiment R is xe2x80x94NR2R3 wherein R2 is cycloropyl and R3 is H.
In one embodiment Ra is chosen from H, monophosphate, diphosphate, and triphosphate.
In one embodiment Ra is chosen from monophosphate, diphosphate, and triphosphate.
In one embodiment Ra is triphosphate.
In one embodiment Ra is H.
In one embodiment, Z is H, OH, xe2x80x94NR2xe2x80x2R3xe2x80x2 wherein:
R2xe2x80x2 is H, or C1-6 alkyl; and
R3xe2x80x2 is H, or C1-6 alkyl.
In one embodiment, R4xe2x80x2 is C1-6alkyl.
In one embodiment, R4xe2x80x2 is methyl or ethyl.
In one embodiment Z is chosen from OH or NH2.
In one embodiment Z is OH.
In another embodiment Z is NH2.
In another embodiment, Y is N.
In another embodiment, Y is Cxe2x80x94X.
In another embodiment, X is H, C1-6alkyl or halogen.
In another embodiment, X is H, methyl or halogen.
In another embodiment, X is methyl, xe2x80x94HCxe2x95x90CH2 and xe2x80x94Cxe2x89xa1CH.
In another embodiment, X is H or halogen.
In another embodiment, X is halogen.
In another embodiment, X is H, methyl or F.
In another embodiment, X is H or F.
In another embodiment, X is H.
In another embodiment, X is F.
It will be appreciated by those skilled in the art that the compounds of formula (I) contain at least two chiral centers which are marked by an asterisk (*) on the general formula (I) or (II) The compounds of formula (I) and (II) thus exist in the form of two different optical isomers (i.e. (+) or (xe2x88x92) enantiomers or xcex2-L and xcex2-D). All such enantiomers and mixtures thereof including racemic mixtures are included within the scope of the invention.
The single optical isomer or enantiomer can be obtained by method well known in the art, such as chiral synthesis, chiral HPLC, enzymatic resolution and chiral auxiliary.
Compounds of the invention include, for compounds having the structure of the formula I:
Compound 1 cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 1(xe2x88x92) (xe2x88x92)cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 1(+) (+)cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 2 cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 2(xe2x88x92) (xe2x88x92)cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane Compound 2(+) (+)cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 3 cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 3(xe2x88x92) (xe2x88x92)cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 3(+) (+)cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 4-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 4(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 4(+) (+)-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 5 cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane; Compound 5(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane; Compound 5(+) (+)-cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 6 cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane; Compound 6(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane; Compound 6(+) (+)-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 7 cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 7(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 7(+) (+)-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 8 cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 8(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 8(+) (+)-cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane 
In a further aspect of the present invention compounds of the invention include
Compound 1(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 2(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 3(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 4(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 5(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 6(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 7(xe2x88x92) (xe2x88x92)-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 8(xe2x88x92) (xe2x88x92)cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane 
In a further embodiment, the compounds of the present invention have a triphosphate group in the 5xe2x80x2 position. In a further aspect of the present invention, the compounds of formula (I) are represented by:
Compound 9 triphosphatecis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 9(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 9(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 10 Triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 10(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane Compound 10(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 11 Triphosphate cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 11(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane; Compound 11(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 12 Triphosphate cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 12(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 12(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 135 Triphosphate cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane; Compound 135(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane; Compound 13(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 14 Triphosphate-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane; Compound 14(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane; Compound 14(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 15 Triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 15(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 15(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 16 Triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 16(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane; Compound 16(+) (+)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane 
In a further aspect of the present invention compounds of the invention include:
Compound 9(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 10(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclobutylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 11(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopentylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 
Compound 12(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2-6xe2x80x2-diamino-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 13(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(guanin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 14(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(adenin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 15(xe2x88x92) (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(2xe2x80x2amino-6xe2x80x2-chloro-purin-9xe2x80x2-yl)-1,3-dioxolane 
Compound 16(xe2x88x92) (xe2x88x92)-triphosphate cis-2-hydroxymethyl-4-(2xe2x80x2amino-purin-9xe2x80x2-yl)-1,3-dioxolane 
In a further embodiment of the present invention the compounds of formula (II) include:
In one embodiment, a compound of formula II is cis-2-hydroxymethyl-4-(cytosin-1xe2x80x2-yl)-1,3-dioxolane (compound#17) 
In one embodiment, a compound of formula II is (xe2x88x92)-cis-2-hydroxymethyl-4-(cytosin-1xe2x80x2-yl)-1,3-dioxolane (xcex2-L-OddC) (compound#17 (xe2x88x92)). 
In one embodiment, a compound of formula II is (+)-cis-2-hydroxymethyl-4-(cytosin-1xe2x80x2-yl)-1,3-dioxolane (xcex2-D-OddC) (compound#17 (+)). 
In another embodiment, a compound of formula II is cis-2-hydroxymethyl-4-(5xe2x80x2-fluorocytosin-1xe2x80x2-yl)-1,3-dioxolane(5FOddC) (compound#18). 
In another embodiment, a compound of formula II is (xe2x88x92)-cis-2-hydroxymethyl-4-(5xe2x80x2-fluorocytosin-1xe2x80x2-yl)-1,3-dioxolane(xcex2-L-5FOddC) (compound#18 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-cis-2-hydroxymethyl-4-(5xe2x80x2-fluorocytosin-1xe2x80x2-yl)-1,3-dioxolane(xcex2-D-5FOddC) (compound#18 (+)). 
In another embodiment, a compound of formula II is cis-2-hydroxymethyl-4-(5xe2x80x2-azacytosin-1xe2x80x2-yl)-1,3-dioxolane (compound#19). 
In another embodiment, a compound of formula II is (xe2x88x92)-cis-2-hydroxymethyl-4-(5xe2x80x2-azacytosin-1xe2x80x2-yl)-1,3-dioxolane (compound#19 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-cis-2-hydroxymethyl-4-(5xe2x80x2-azacytosin-1xe2x80x2-yl)-1,3-dioxolane(compound#19 (+)). 
In another embodiment, a compound of formula II is cis-2-hydroxymethyl-4-(5xe2x80x2-methylcytosin-1xe2x80x2-yl)-1,3-dioxolane(compound#20). 
In another embodiment, a compound of formula II is (xe2x88x92)-cis-2-hydroxymethyl-4-(5xe2x80x2-methylcytosin-1xe2x80x2-yl)-1,3-dioxolan (compound#20 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-cis-2-hydroxymethyl-4-(5xe2x80x2-methylcytosin-1xe2x80x2-yl)-1,3-dioxolane (compound#20 (+)). 
In another embodiment, a compound of formula II is cis-2-hydroxymethyl-4-(N-1xe2x80x2-thyminyl)-1,3-dioxolane(compound#21). 
In another embodiment, a compound of formula II is (xe2x88x92)-cis-2-hydroxymethyl-4-(N-1xe2x80x2-thyminyl)-1,3-dioxolane (compound#21 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-cis-2-hydroxymethyl-4-(N-1xe2x80x2-thyminyl)-1,3-dioxolane (compound#21 (+)). 
In a further embodiment, the compounds of the present invention have a triphosphate group in the 5xe2x80x2 position. In a further aspect of the present invention, the compounds of formula (II) are represented by:
In one embodiment, a compound of formula II is triphosphate-cis-2-hydroxymethyl-4-(cytosin-1xe2x80x2-yl)-1,3-dioxolane (xcex2-OddC-tp) (compound#22). 
In one embodiment, a compound of formula II is (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(cytosin-1xe2x80x2-yl)-1,3-dioxolane (xcex2-L-OddC-tp) (compound#22 (xe2x88x92)). 
In one embodiment, a compound of formula II is (+)-triphosphate-cis-2-hydroxymethyl-4-(cytosin-1xe2x80x2-yl)-1,3-dioxolane (xcex2-D-OddC-tp) (compound#22 (+)). 
In another embodiment, a compound of formula II is triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-fluorocytosin-1xe2x80x2-yl)-1,3-dioxolane(xcex2-5FOddC-tp) (compound#23). 
In another embodiment, a compound of formula II is (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-fluorocytosin-1xe2x80x2-yl)-1,3-dioxolane(xcex2-L-5FOddC-tp) (compound#23 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-fluorocytosin-1xe2x80x2-yl)-1,3-dioxolane(xcex2-D-5FOddC-tp) (compound#23 (+)). 
In another embodiment, a compound of formula II is triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-azacytosin-1xe2x80x2-yl)-1,3-dioxolane(compound#24). 
In another embodiment, a compound of formula II is (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-azacytosin-1xe2x80x2-yl)-1,3-dioxolane(compound#24 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-azacytosin-1xe2x80x2-yl)-1,3-dioxolane(compound#24 (+)). 
In another embodiment, a compound of formula II is triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-methylcytosin-1xe2x80x2-yl)-1,3-dioxolane (compound#25). 
In another embodiment, a compound of formula II is (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-methylcytosin-1xe2x80x2-yl)-1,3-dioxolane (compound#25 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-triphosphate-cis-2-hydroxymethyl-4-(5xe2x80x2-methylcytosin-1xe2x80x2-yl)-1,3-dioxolane(compound#25 (+)). 
In another embodiment, a compound of formula II is triphosphate-cis-2-hydroxymethyl-4-(N-1xe2x80x2-thyminyl)-1,3-dioxolane (compound#26). 
In another embodiment, a compound of formula II is (xe2x88x92)-triphosphate-cis-2-hydroxymethyl-4-(N-1xe2x80x2-thyminyl)-1,3-dioxolane(compound#26 (xe2x88x92)). 
In another embodiment, a compound of formula II is (+)-triphosphate-cis-2-hydroxymethyl-4-(N-1xe2x80x2-thiminyl)-1,3-dioxolane (compound#26 (+)). 
In one embodiment the compounds of the present invention are provided in the form of a single enantiomer at least 95% free of the corresponding enantiomer.
In one embodiment the compounds of the present invention are provided in the form of a single enantiomer at least 95% free of the corresponding enantiomer.
In one embodiment the compounds of the present invention are provided in the form of a single enantiomer at least 99% free of the corresponding enantiomer.
In an other embodiment the compound of the present invention are in the form of the (+) enantiomer at least 95% free of the corresponding (xe2x88x92) enantiomer.
In an other embodiment the compound of the present invention are in the form of the (+) enantiomer at least 97% free of the corresponding (xe2x88x92) enantiomer.
In an other embodiment the compound of the present invention are in the form of the (+) enantiomer at least 99% free of the corresponding (xe2x88x92) enantiomer.
In an other embodiment embodiment, the compound of the present invention are in the form of the (xe2x88x92) enantiomer at least 95% free of the corresponding (+) enantiomer.
In an other embodiment the compound of the present invention are in the form of the (xe2x88x92) enantiomer at least 97% free of the corresponding (+) enantiomer.
In an other embodiment the compound of the present invention are in the form of the (xe2x88x92) enantiomer at least 99% free of the corresponding (+) enantiomer.
There is also provided a pharmaceutically acceptable salts of the present invention. By the term pharmaceutically acceptable salts of compounds of general formula (I) and (II) are meant those derived from pharmaceutically acceptable inorganic and organic acids and bases. Examples of suitable acids include hydrochloric, hydrobromic, sulphuric, nitric, perchloric, fumaric, maleic, phosphoric, glycollic, lactic, salicylic, succinic, toleune-p-sulphonic, tartaric, acetic, citric, methanesulphonic, formic, benzoic, malonic, naphthalene-2-sulphonic and benzenesulphonic acids. Other acids such as oxalic, while not in themselves pharmaceutically acceptable, may be useful as intermediates in obtaining the compounds of the invention and their pharmaceutically acceptable acid addition salts.
Salts derived from appropriate bases include alkali metal (e.g. sodium), alkaline earth metal (e.g. magnesium), ammonium and NR4+ (where R is C1-4 alkyl) salts.
References hereinafter to a compound according to the invention includes compounds of the general formula (I) and (II) and there pharmaceutically acceptable salts.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
As used in this application, the term xe2x80x9calkylxe2x80x9d represents an unsubstituted or substituted (by a halogen, nitro, CONH2, COOH, Oxe2x80x94C1-6 alkyl, Oxe2x80x94C2-6 alkenyl, Oxe2x80x94C2-6 alkynyl, hydroxyl, amino, or COOQ, wherein Q is C1-6 alkyl; C2-6 alkenyl; C2-6 alkynyl) straight chain, branched chain or cyclic hydrocarbon moiety (e.g. isopropyl, ethyl, fluorohexyl or cyclopropyl). The term alkyl is also meant to include alkyls in which one or more hydrogen atoms is replaced by an halogen, more preferably, the halogen is fluoro (e.g. CF3xe2x80x94 or CF3CH2xe2x80x94).
The terms xe2x80x9calkenylxe2x80x9d and xe2x80x9calkynylxe2x80x9d represent an alkyl containing at least one unsaturated group (e.g. allyl).
The term xe2x80x9ccycloalkylxe2x80x9d represents an alkyl which is cyclic, such as cyclopropyl, cyclopentyl or cyclobutyl.
The term xe2x80x9chydroxy protecting groupxe2x80x9d is well known in the field of organic chemistry. Such protecting groups may be found in T. Greene, Protective Groups In Organic Synthesis, (John Wiley and Sons, 1981). Example of hydroxy protecting groups include but are not limited to acetyl-2-thioethyl ester, pivaloyloxymethyl ester and isopropyloxycarbonyloxymethyl ester.
The term xe2x80x9carylxe2x80x9d represent an unsaturated carbocyclic moiety, optionally mono- or di-substituted with OH, SH, amino, halogen or C1-6 alkyl.
The term xe2x80x9cheteroarylxe2x80x9d represent an aryl wherein at least one carbon ring atom is substituted by an heteroatom (e.g. N, O, or S).
The term xe2x80x9caminoalkylxe2x80x9d represent an alkyl which is covalently bonded to the adjacent atom through a nitrogen atom.
The term xe2x80x9cthioalkylxe2x80x9d represent an alkyl which is covalently bonded to the adjacent atom through a sulfur atom.
The term xe2x80x9calkoxylxe2x80x9d represent an alkyl which is covalently bonded to the adjacent atom through an oxygen atom.
When there is a sulfur atom present, the sulfur atom can be at different oxydation level, S, SO, or SO2. All such oxydation level are within the scope of the present invention.
The term xe2x80x9chostxe2x80x9d represent any mammals including humans.
In one embodiment, the host is human.
The compounds of the present invention can be prepared by methods well known in the art. For example, such methods are described in the following references: U.S. Pat. No. 5,041,449, PCT publication WO 92/20669 (PCT application PCT/CA92/00211), Journal of Chromatography, 645 (1993) 107-114, Tetrahedron Assymetry Vol. 4 No. 11 pp2319-2322 (1993), Tetrahedron Assymetry Vol. 4 No. 2 pp211-214 (1993), Bioorganic and Medicinal Chemistry Vol.3 No.8, pp.1543-1546 (1993), Tetrahedron Letters, Vol.33, No. 46, pp 6949-6952, (1992), J.Org. Chem., 34(6), 1547-1550 (1969), J.Org. Chem., 52(9), 1794-1801 (1987), J.Am.Chem.Soc., 87(8), 1785-1788 (1965), J.Org. Chem. (1989), 54, 631-635. which are all incorporated by reference.
According to one embodiment, it will be appreciated that the amount of a compound of the present invention required for use in treatment will vary not only with the particular compound selected but also with the route of administration, the nature of the condition for which treatment is required and the age and condition of the patient and will be ultimately at the discretion of the attendant physician or veterinarian. In general however a suitable dose will be in the range of from about 0.01 to about 750 mg/kg of body weight per day, preferably in the range of 0.5 to 60 mg/kg/day, most preferably in the range of 1 to 20 mg/kg/day.
The desired dose according to one embodiment is conveniently presented in a single dose or as divided dose administered at appropriate intervals, for example as two, three, four or more doses per day.
In another embodiment, the compound is conveniently administered in unit dosage form; for example containing 10 to 1500 mg, conveniently 20 to 1000 mg, most conveniently 50 to 700 mg of active ingredient per unit dosage form.
According to another embodiment of the present invention, the active ingredient is administered to achieve peak plasma concentrations of the active compound of from about 1 to about 75 xcexcM, preferably about 2 to 50 xcexcM, most preferably about 3 to about 30 xcexcM. This may be achieved, for example, by the intravenous injection of a 0.1 to 5% solution of the active ingredient, optionally in saline, or orally administered as a bolus containing about 1 to about 500 mg of the active ingredient. Desirable blood levels may be maintained by a continuous infusion to provide about 0.01 to about 5.0 mg/kg/hour or by intermittent infusions containing about 0.4 to about 15 mg/kg of the active ingredient.
While it is possible that, for use in therapy, a compound of the present invention may be administered as the raw chemical, it is preferable according to one embodiment of the invention, to present the active ingredient as a pharmaceutical formulation. The embodiment of the invention thus further provides a pharmaceutical formulation comprising a compound of formula (I),or formula (II), or a pharmaceutically acceptable salt thereof together with one or more pharmaceutically acceptable carriers therefor and, optionally, other therapeutic and/or prophylactic ingredients. The carrier(s) must be xe2x80x9cacceptablexe2x80x9d in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.
According to one embodiment of the present invention, pharmaceutical formulations include but are not limited to those suitable for oral, rectal, nasal, topical (including buccal and sub-lingual), transdermal, vaginal or parenteral (including intramuscular, sub-cutaneous and intravenous) administration or in a form suitable for administration by inhalation or insufflation. The formulations may, where appropriate, be conveniently presented in discrete dosage units and may be prepared by any of the methods well known in the art of pharmacy. All methods according to this embodiment include the step of bringing into association the active compound with liquid carriers or finely divided solid carriers or both and then, if necessary, shaping the product into the desired formulation.
According to another embodiment, pharmaceutical formulation suitable for oral administration are conveniently presented as discrete units such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules. In another embodiment, the formulation is presented as a solution, a suspension or as an emulsion. Still in another embodiment, the active ingredient is presented as a bolus, electuary or paste. Tablets and capsules for oral administration may contain conventional excipients such as binding agents, fillers, lubricants, disintegrants, or wetting agents. The tablets may be coated according to methods well known in the art. Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous vehicles (which may include edible oils), or preservatives.
The compounds of the present invention according to an embodiment are formulated for parenteral administration (e.g. by injection, for example bolus injection or continuous infusion) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing an/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use.
For topical administration to the epidermis, the compounds, according to one embodiment of the present invention, are formulated as ointments, creams or lotions, or as a transdermal patch. Such transdermal patches may contain penetration enhancers such as linalool, carvacrol, thymol, citral, menthol and t-anethole. Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also contain one or more emulsifying agents, stabilizing agents, dispersing agents, suspending agents, thickening agents, or colouring agents.
Formulations suitable for topical administration in the mouth include lozenges comprising active ingredient in a flavoured base, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.
Pharmaceutical formulations suitable for rectal administration wherein the carrier is a solid. In another embodiment, they are presented as unit dose suppositories. Suitable carriers include cocoa butter and other materials commonly used in the art, and the suppositories may be conveniently formed by admixture of the active compound with the softened or melted carrier(s) followed by chilling and shaping in moulds.
According to one embodiment, the formulations suitable for vaginal administration are presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.
For intra-nasal administration the compounds, in one embodiment of the invention, are used as a liquid spray or dispersible powder or in the form of drops. Drops may be formulated with an aqueous or non-aqueous base also comprising one more dispersing agents, solubilising agents or suspending agents. Liquid sprays are conveniently delivered from pressurized packs.
For administration by inhalation the compounds, according to one embodiment of the invention are conveniently delivered from an insufflator, nebulizer or a pressurized pack or other convenient means of delivering an aerosol spray. In another embodiment, pressurized packs comprise a suitable propellant such as dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In another embodiment, the dosage unit in the pressurized aerosol is determined by providing a valve to deliver a metered amount.
Alternatively, in another embodiment, for administration by inhalation or insufflation, the compounds according to the present invention are in the form of a dry powder composition, for example a powder mix of the compound and a suitable powder base such as lactose or starch. In another embodiment, the powder composition is presented in unit dosage form in, for example, capsules or cartridges or e.g. gelatin or blister packs from which the powder may be administered with the aid of an inhalator or insufflator.
In one embodiment, the above described formulations are adapted to give sustained release of the active ingredient.
The compounds of the invention may also be used in combination with other antiviral agents.
In one embodiment, the compounds of the invention may be employed together with at least one other antiviral agent chosen from protease inhibitors, polymerase inhibitors, and helicase inhibitors.
As used in this application, the term xe2x80x9cinterferonxe2x80x9d include: interferon likes molecules such as interferon (IFN), interferon xcex1-2a, interferon xcex1-2b, consensus interferon (CIFN) and other types of interferons.
In one embodiment, the compounds of the invention may be employed together with at least one other antiviral agent chosen from interferon (IFN), interferon xcex1-2a, interferon xcex1-2b, consensus interferon (CIFN), ribavirin, amantadine, rimantadine, interleukine-12, ursodeoxycholic acid (UDCA), glycyrrhizin and silybum marianum.
In one embodiment, the compounds of the invention may be employed together with at least one other antiviral agent chosen from Interferon-xcex1, Ribavirin and Amantadine.
In one embodiment, the compounds of the invention may be employed together with at least one other antiviral agent chosen from Interferon-xcex1 and Ribavirin (REBETRON).
In one embodiment, the compounds of the invention may be employed together Interferon-xcex1.
In one embodiment, the compounds of the invention may be employed together with Ribavirin.
The combinations referred to above may conveniently be presented for use in the form of a pharmaceutical formulation and thus pharmaceutical formulations comprising a combination as defined above together with a pharmaceutically acceptable carrier therefor comprise a further aspect of the invention.
The individual components of such combinations may be administered either sequentially or simultaneously in separate or combined pharmaceutical formulations.
When the compound (I), or (II) or a pharmaceutically acceptable salts thereof is used in combination with a second therapeutic agent active against the same virus the dose of each compound may be either the same as or differ from that when the compound is used alone. Appropriate doses will be readily appreciated by those skilled in the art.
The following examples are provided to illustrate various embodiments of the present invention and shall not be considered as limiting in scope.
Scheme 1 
The target compound can be prepared according to the above scheme:
Step a: 2-benzoyloxy-acetaldehyde I reacted with methyl (R)-(+)-2,2-dimethyl-1,3-dioxolane-4-carboxylate II in the presence para-toluene sulfonic acid (pTSA) under transketalisation to give 2-benzoyloxymethyl-1,3-dioxolane-4-carboxylmethyl ester III as a mixture of cis and trans isomers in a ratio of 3:1 in favor of cis isomer.
Step b: The carboxylic methyl ester III was selectively hydrolysed using lithium hydroxide to give the corresponding acid derivatives IVa and IVb. The mixture were separated by flash chromatography and each isomer was further used independently.
Step c: The carboxylic function of IVa was then converted to an acetoxy leaving group by treatment with lead tetraacetate.
Step d: The (2R)-2-benzoyloxymethyl-1,3-dioxolane-4-acetoxy IVa was coupled with silylated 2-amino-6-chloropurine using trimethylsilyl trifluoromethylsulfonate (TMSTf) as activator to give a mixture of cis and trans isomers of nucleoside analogues VIa and VIb in a ratio of 1.2:1 in favor of cis isomer. The mixture was separated by flash chromatography and each isomer was used independently further.
Step e: The (xe2x88x92)-(2R,4R)-2-benzoyloxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-chloro-purine-9xe2x80x2-yl)-1,3-dioxolane VIa was treated with cyclopropylamine in ethanol to give the corresponding (xe2x88x92)-(2R,4R)-2-benzoyloxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane VII in good yield.
Step f: Removal of benzoyl protecting group was achieved by treatment of (xe2x88x92)-(2R,4R)-2-benzoyloxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane VII with methanolic ammonia to give the desired product (xe2x88x92)-(2R,4R)-2-hydroxymethyl-4-(2xe2x80x2-amino-6xe2x80x2-cyclopropylamino-purine-9xe2x80x2-yl)-1,3-dioxolane 1(xe2x88x92) in good yield.